Marcia38
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Joined: Mon Mar 09, 2020 2:11 pm
Occupation: Parent

Salt crystallization measurement

Postby Marcia38 » Mon Mar 09, 2020 2:34 pm

My 5th grade daughter is doing a science project experiment comparing salt crystallization from Iodized vs non-iodized salt. She used a pencil and string for the crystals to attach to but we are now trying to figure how we can measure the crystals growth for her data chart and graph. The crystals have formed the entire length of the strings but vary in width. We appreciate any suggestions. Thanks!

audreyln
Expert
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Joined: Fri Oct 01, 2010 7:28 am
Occupation: Engineer - Chemical

Re: Salt crystallization measurement

Postby audreyln » Tue Mar 10, 2020 2:15 pm

Hello,

Sounds like a fun project! To measure the size of the crystals formed you could consider either measuring their weight or their volume. Measuring their length/width may be more difficult as you've identified.

To measure their weight you'll need a sensitive scale. One you would use in the kitchen to measure baking ingredients would work well. Ideally you would have weighed the pencil/string apparatus prior to submerging so you could subtract the weight of the pencil/string from the final weight. Assuming you didn't, I would first try to prepare the crystals so the amount of string is the same in each sample and remove the pencil if possible. You don't want a longer string or heavier pencil in one sample affecting your results.

Alternatively you could measure the volume of the crystals. To do this you'll need a graduated cylinder filled with water. Note the volume of water in the cylinder (ex. 100 ml), then submerge your crystal in the water and note the new volume (ex. 110ml). This would tell you the volume of your crystal is 10 ml which is also equal to 10 cubic centimeters.

Good luck,

Audrey

Yasmin_Hussain
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Joined: Wed Jun 17, 2020 10:08 pm
Occupation: Other Adult

Re: Salt crystallization measurement

Postby Yasmin_Hussain » Mon Jul 27, 2020 8:28 pm

you can put on both measurement, the height and the width. Since the salt crystallization will be different from time to time you can put on the graph day x size.

you can calculate the size by multiply the height and the width. by then you can calculate the size better.


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